Tmax, xtol and zone densities question..helpgreenspun.com : LUSENET : Large format photography : One Thread
This is my first venture in to processing 4x5 tmax film (or any film) in a jobo processor (cpp2). I am shooting tmax 100 @ asa 125. I am processing it in xtol 1:1 @ 70 degrees for 9min 15sec, agitation speed 3 (aprox 50 rpm), using a 3010 expert drum. My zone 1 and 8 densities are ok at .11 and 1.30 respectively. However, I am getting a zone 5 density of .92, which is high compared to the .70-.75 range I usually get with all films that I hand develop. When I exposed tmax @asa100 and developed for 9min in xtol 1:1 the zone 1 and 8 densities were .17 and 1.34. The zone 5 density was about 1.00.......very high. My meter is dead on, etc. Should I be concerned about the desity of my zone 5 reading? It just seems to be out of line with all of my previous experience. If so, any ideas on how to bring things more in line with my expectations.
-- Michael kwiatkowski (firstname.lastname@example.org), April 25, 2001
That does sound a bit odd. It sounds like you have ended up with some compensation i.e., a shoulder in the characteristic curve. In my experience, if anything, continuous agitation in rotary processing leads to the exact opposite i.e., increase in highlight separation and a somewhat flatter toe.
Re whether you should be concerned, I guess it depends on the kind of picture. It will provide better local contrast in the shadows and midtones but flatter local contrast in the highlights. If that seems appropriate to the pictures you're making, the negatives should be fine.
I'm still intrigued by the compensation you've got with rotary development. Did you use a pre-soak? DJ
-- N Dhananjay (email@example.com), April 25, 2001.
No, I did not pre-soak. According to Kodak and Jobo, one should not use a presoak with xtol.....
-- michael kwiatkowski (firstname.lastname@example.org), April 25, 2001.
Michael How is your meter "dead on"? Is it calibrated to a known light source? Do you know for a fact that it is linear? and how did you change exposure on your tests. By f stop only or by shutter speed. When was the last time you had your shutter speeds checked. How much are they off at each end of the scale. What is the base plus fog density of your film. Kevin
-- Kevin Kolosky (email@example.com), April 26, 2001.
My guess is that it's one of Xtols well-known partial failures, and just a co-incidence that it happened when you switched processing methods. Try a fresh batch of Xtol before you change anything else.
-- Pete Andrews (firstname.lastname@example.org), April 26, 2001.
If you adjust zones 1 and 8 with exposure and processing time to get the densities you want, zone 5 is going to be a function of the film and developer combination and is just going to fall where it falls.
Have you read Beyond the Zone System? You are certainly someone who would stick to it and benefit from it.
-- John H. Henderson (email@example.com), April 26, 2001.
Tmax films have a bit more red sensitivity than normal films. What was the color of the Zone V area you used? This could be part of what is giving you trouble. You might try backing the TMax sheet with one of TriX or a normal film & processing it & seeing if one or two specific colored objects come out much differently. If so, it may just be the color as rendered by the film.
-- Dan Smith (firstname.lastname@example.org), April 26, 2001.
I'll say a bit more about my methods.. For my zone V measurement I use a grey card in open shade. All areas of the card measure the same. I check it with three meters (two spot and a spot on a 35mm slr) all read the exact same. I change zones by changing the f/stop. My methods have been the same for about fifteen years and I have not had a result such as this until I went with the cpp (although I have not used tmax before). It does not seem to be an "xtol failure" as I would think it would produce a result on the ends of the scale or probably even evident to the eye. John, I do not have Beyond the zone system although I have read it and was probably resigned to your conclusion. It would be nice to find a way to have a more even seperation in the negative though. I hate taking too much time with this testing stuff... I want to shoot some film! I want to start using Tmax because of the ability to carry more readyloads in my small backpack. I thought that Delta and tmax would behave "relatively" the same. I might be wrong.. Thanks so much for all the replies
-- michael kwiatkowski (email@example.com), April 26, 2001.
OK I've never used a drum processor before but from what I understand it is constant agitation. So, could the agitation be off? Too much agitation can boost contrast, no?
-- Dominique Labrosse (firstname.lastname@example.org), April 26, 2001.
Sorry to keep plugging at the Xtol failure issue Michael, but I don't see what else it can be.
What you've described is that the mid curve density is high compared to Dmax. Looked at another way, what you're saying is that Dmax is curtailed, and the prime suspect for this scenario is weakened developer.
From the density readings you've given, you have a gamma of about 0.67 up to 'zone5', and then from 'zone5' up to 'zone8' you only have an average gamma of 0.42!
Now Tmax should give an incredibly long, straight curve, and your density at zone8 should easily have reached 1.4. It didn't, and the only reason I can think of for this is exhausted developer.
The fact that your zone5 density is higher than expected is most likely due to the continuous agitation of the Jobo, and I further suspect that with good developer the zone8 density would have been correspondingly high.
-- Pete Andrews (email@example.com), April 27, 2001.
I'm going to be slightly insulting and ask if you're 100% sure you mixed the developer right. I work in a commmunial lab at college. When I first ran my test strips to standardize my Jobo developing, I was seeing the same phenomenon you are. I was quite puzzled, so I took the graph to the Prof that teaches Zone. It turned out that the lab manager had mixed that weeks batch of XTOL about 15% weak. It was remixed and everything's cool.
-- Ty Williams (firstname.lastname@example.org), April 27, 2001.
I agree with most answers...Before you do anything else,,,check your developer...I would toss and mix a new batch verry carefully ..then try again. I think this will solve your problem.. Best of luck..... Gary..(-:
-- Gary Ross (email@example.com), April 30, 2001.